Douglas Laboratories N Acetyl L Cysteine 600 mg Dominican Republic Ubuy 5 Route of synthesis of glutathione (GSH) involving three amino acids Download Scientific Diagram As I mention in my book, N acetyl cysteine (NAC) is not found in food sources, but in the body, it converts into cysteine. NAC acts as a precursor to glutathione, a powerful NAC N Acetyl L Cysteine Allergy Research Group N Acetyl Cysteine (Glutathione Precursor)